The blow mould known from DE 69 42 384 T2 has two arms which are hinged like pliers to an axis. Each arm carries three juxtaposed mould halves. Both arms are pivoted to each other by knee lever drives constituting a shutting device until the mould halves reach their closing position. The ends of the arms remote from the connecting axis are provided with abutment faces on which a C-shaped clamp, defining a closing device, is pushed from the side opposed to the connecting axis. The closing force of the clamp is transmitted on each pair of mould halves indirectly via the arms and with relatively long lever arms with respect to the connecting axis which therefore has to stand a significant part of the reaction forces and blow pressure. Several drives and drive control systems are needed for the closing device and device holding the closed state.
Both mold halves of the blow mold known from DE 19 11 600 A are pivotally held directly at the connecting axis. Complex centering surface arrangements are provided in the mold separation plane in order to prevent an offset between both mold halves in the closed position.
U.S. Pat. No. 3,195,186 A discloses to fix in an injection moulding machine a compressed package of several mould parts from both lateral sides by means of U-shaped clamping devices which engage at edge regions of the package. Additionally, downholders are provided which are oriented perpendicular to the mould separation planes which downholders press between the clamping devices against the top and bottom sides of the package.